Cooling Device

ABSTRACT

A cooling device is in the form of a refrigerator or a point-of-sale display cabinet that is open on one side and is used to store and present perishable goods. The device is fitted with a unit for lowering the interior temperature in relation to the ambient temperature. The inner wall is constructed in two stages, the outer layer consisting of a thermal insulation layer having a heat conductivity &lt;1 Watt/K, and the inner layer consisting of an at least partially coated mixture consisting of a phase transition material and graphite, which covers at least part of the inner wall and is used as a cold accumulator layer.

The invention relates to a cooling device in the form of a refrigerator or of a point-of-sale display cabinet, open on one side, for the storage and presentation of perishable goods, which is equipped with an assembly for lowering the internal temperature with respect to the ambient temperature.

Such cooling devices, depending on the quantity of the exchanged contents or refrigeration stock, on the thermal insulation with respect to the surroundings and on the structurally induced losses, require, to maintain the temperature difference between the ambient temperature and the desired internal temperature, correspondingly designed cooling assemblies which are to ensure as high a constancy of the selected internal temperature as possible.

Whereas the energy quantity to be discharged for the structurally induced losses and for the thermal insulation can be determined relatively accurately and therefore can be taken into account in the design of the required cooling assembly, the incalculable quantity of exchanged goods necessitates an over-dimensioning of the power of the cooling assembly in order to cope with peak loads.

Since the principle exchange of goods and therefore the peak loads occur in the period of time when there is generally the highest energy demand, a reduction in the peak load is particularly desirable for the energy industry, since this is associated with price-related and economic advantages in terms of the power requirement outside the peak time. In developing countries, repeated power failures must also be expected. These regions are faced with the problem of an effective protection of the refrigeration stock.

The set object of the invention is to specify a cooling device which makes it possible to reduce the peak power of the cooling assembly used and which at the same time affords protection for the refrigeration stock in the event of a power failure.

Furthermore, the set objects of the invention are:

-   -   a) to achieve the lowering of temperature in the introduced         refrigeration stock as quickly as possible; and     -   b) to transport the cold to the refrigeration stock more         quickly; and     -   c) to supply bottle bundles with cold rapidly;     -   d) to connect a plurality of refrigerators or chill cabinets in         series and supply them with cooling water which is cooled down         and made available centrally.

According to the invention, the object is achieved by means of a cooling device in the form of a refrigerator or of a point-of-sale display cabinet, open on one side, for the storage and presentation of perishable goods, which is equipped with an assembly for lowering the internal temperature with respect to the ambient temperature, and in which the inner wall is of two-stage construction, the outer layer consisting of a thermal insulating layer 1 with a thermal conductivity <1 watt/K, and the inner layer consisting of an at least partially encased mixture of a phase transition material and graphite, which mixture covers at least part of the inner wall and serves as a cold accumulator layer 2.

The inner layer serving as a cold accumulator makes it possible to utilize a cooling assembly having a lower cooling or peak power. The load peaks are markedly reduced by means of the proposed configuration, since a cold store or cold buffer is present which compensates the peak load.

Advantageously, according to the invention, the cooling device is configured such that the lowering of the internal temperature is ensured by evaporator plates or Peltier elements which are arranged between the insulating layer 1 and the layer consisting of phase transition material and graphite. It is particularly important in this case to use a pure graphite material between the cold store and cold source, in order to accelerate the cold flow and make contact more efficient (cold bridge). As a result, a more rapid and more uniform supply and distribution of temperature, boosting and regeneration in the wall accumulator, as an integrated component of the cooling device, are achieved.

The embodiment of the cooling device is particularly preferred whereby the inner walls are provided with grooves or indentations into which are pushed cold conduction floors 3 which are in direct thermal contact with the cold accumulator layer 2, while, furthermore, the cold conduction floors 3 preferably consist of encased plates which at least partially contain a mixture of a phase transition material and graphite. Such a configuration improves the dissipation of heat from the goods to be cooled.

Alternatively to this, the cold conduction floors 3 consist of graphite plastic.

Moreover, advantageously, additional plate-shaped cold accumulators 4 or cold storage containers or boxes are provided, which are arranged removably in the region of the inner wall or of the cold conduction floors 3. Such additional plate-shaped cold accumulators 4, on the one hand, increase the capacity of the cooling device for buffering peak loads and, on the other hand, can be used as transportable cold stores which are used in transport containers for an uninterrupted transport of refrigeration stock and which consequently make it possible to have a continuous or uninterrupted cooling chain.

An embodiment of the cooling device according to the invention is preferred, furthermore, in which, especially for drinks bottles, expandable shafts 5 are present, which are arranged vertically or horizontally and the wall of which consists of a layer of a mixture, encased with expandable plastic, of a phase transition material and graphite, or of wall segments connected expandably to one another and containing encased phase transition material and graphite. This embodiment allows a rapid cooling of drinks.

Preferably, the casing of the cold accumulator layer 2, of the additional cold accumulators 4 and of the cold conduction floors 3 consists of an enameled metal, of a plastic or of a lacquer layer. The graphite used is in this case preferably an expanded and recompacted material, and the phase transition material used is selected from the class of materials with a phase change in the range of −30° C. to 15° C.

Preferably, in the case of chill cabinets, the supply of cooling medium is regulated centrally via a heavy-duty flow cooler, the individual chill cabinets being connected to one another via a line 6 carrying the cooling medium.

The cooling device according to the invention is used particularly preferably as a point-of-sale display cabinet 7 open on one side.

Further particulars and more detailed explanations are presented in the following figures which are to illustrate the invention by way of example.

FIG. 1 cross section through a cooling device with a thermal insulating layer and cold accumulator layer

FIG. 2 detail of a cooling device with a cold accumulator layer and indentations for cold conduction floors

FIG. 3 cross section through a cooling device with bottle shafts in a horizontal and vertical arrangement

FIG. 4 cross section through a cooling device with removable cold storage plates

FIG. 5 cross section through a cooling device with a central cooling assembly and with two or more chill cabinets which are supplied via a ring line with cooling medium which boosts the cold accumulators.

FIG. 1 shows the cross section through a cooling device according to the invention, in which the right and left side walls inside the cooling device and the thermal insulating layer 1 are covered by a cold accumulator layer 2. The evaporator plates, lines 7 carrying cooling medium or Peltier elements are in this case preferably arranged between the insulating layer 1 and the cold accumulator layer 2.

A detail of a cooling device according to the invention is illustrated in FIG. 2. The inner walls are provided with grooves into which cold conduction floors 3 are pushed. The cold conduction floors 3 are in direct thermal contact with the cold accumulator layer 2 forming the inner wall of the cooling device and with the cooling containers located on it or with refrigeration stock provided with cooling films.

FIG. 3 shows a cross section through a cooling device according to the invention with bottle shafts 5 in a horizontal and vertical arrangement. The bottle shafts 5 are configured such that their wall consists of a layer of a mixture, encased with expandable plastic, of a phase transition material and graphite, or of wall segments connected expandably to one another and containing encased phase transition material and graphite.

A cross section through a further embodiment according to the invention of a cooling device with removable cold storage plates is illustrated in FIG. 4. The additional plate-shaped cold accumulators 4 are arranged removably in the region of the cold accumulator layer 2 forming the inner wall. Lines 6 through which cooling medium flows are in this case embedded into the cold accumulator layer 2.

Finally, FIG. 5 shows a cross section through a cooling device according to the invention with a central cooling assembly and with two or more chill cabinets 7 which are supplied with cooling medium via a ring line 6. A common cooling assembly which is set up outside the sales space ensures the control of the temperature of the cooling medium and, via heat exchange between the cooling medium and the cold accumulator layer 2, boosts the latter with useful energy absorption capacity as a result of the phase transformation of the phase transition material. 

1-12. (canceled)
 13. A cooling device, comprising: a housing with a wall forming a refrigerator or a point-of-sale display cabinet for storing and presenting perishable goods; an assembly for lowering an internal temperature of said housing with respect to ambient temperature; said wall having a two-layer construction with an outer layer formed of a thermal insulating layer with a thermal conductivity <1 Watt/K and an inner layer formed of an, at least partially encased, mixture of a phase transition material and graphite, said mixture covering at least a part of said wall and serving as a cold accumulator.
 14. The cooling device according to claim 13, wherein said assembly for lowering the interior temperature includes evaporator plates or Peltier elements disposed between said insulating layer and said cold accumulator formed of the phase transition material and graphite.
 15. The cooling device according to claim 14, which comprises a graphite plate mounted as a cold bridge between said evaporator plates or Peltier elements and said cold accumulator.
 16. The cooling device according to claim 13, wherein said inner walls have recesses formed therein and cold conduction floors pushed into said recesses, and wherein said cold conduction floors are in direct thermal contact with said layer forming said cold accumulator and with cooling containers or cooling films.
 17. The cooling device according to claim 16, wherein said cold conduction floors consist of encased plates which at least partially contain a mixture of a phase transition material and graphite.
 18. The cooling device according to claim 16, which further comprises additional plate-shaped cold accumulators removably disposed in a region of said inner wall or of said cold conduction floors.
 19. The cooling device according to claim 13, which further comprises additional plate-shaped cold accumulators removably disposed at said inner wall.
 20. The cooling device according to claim 13, wherein an interior of said housing is formed with expandable shafts configured for drinks bottles and aligned vertically or horizontally, said expandable shafts having walls formed of a layer of a mixture, encased with expandable plastic, of a phase transition material and graphite.
 21. The cooling device according to claim 13, wherein an interior of said housing is formed with expandable shafts configured for drinks bottles and aligned vertically or horizontally, said expandable shafts having wall segments connected expandably to one another and containing encased phase transition material and graphite.
 22. The cooling device according to claim 13, which comprises an encasing of said cold accumulator layer formed of a material selected from the group consisting of an enameled metal, a plastic, or a lacquer layer.
 23. The cooling device according to claim 18, which comprises an encasing of said cold accumulator layer, said additional cold accumulators, and of said cold conduction floors formed of a material selected from the group consisting of an enameled metal, a plastic, or a lacquer layer.
 24. The cooling device according to claim 13, wherein said graphite is an expanded and recompacted material.
 25. The cooling device according to claim 13, wherein said assembly for lowering the interior temperature includes a plurality of cooling devices with a common line through which a cooling fluid flows and which is embedded in said layer forming said cold accumulator.
 26. The cooling device according to claim 13, wherein said phase transition material is selected from a class of materials with a phase change in a temperature range from −30° C. to 15° C.
 27. The cooling device according to claim 13 formed as a point-of-sale display cabinet open on one side. 